55 lines
2.5 KiB
Markdown
55 lines
2.5 KiB
Markdown
# Binary Search
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**Binary search**, also known as half-interval **search**, logarithmic **search**, or **binary** chop, is a **search** algorithm that finds the position of a target value within a sorted array. **Binary search** compares the target value to the middle element of the array.
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1. Time Complexity: O(log n)
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2. Space Complexity: O(1)
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3. Applications: Best when data is sorted and large
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4. Founder's Name: P.F. Windley, A.D. Booth, A.J.T. Colin, and T.N. Hibbard
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5. It is one of the popular and daily using Searching Algorithm
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## Steps
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1. Find the middle element of the array
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2. Check whether the key is equal to middle element if yes then return the index and exit the program
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3. If the 2 step didn't run then test whether the element is less than the middle element if yes then run the step: 1 between the start to middle-1 index
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4. If the 3 step didn't run then test whether the element is higher than the middle element if yes then run the step: 1 between the middle+1 to the last index.
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5. Run the loop till the starting index is less than end index
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6. If the loop over and data not found then return -1 that means data doesn't exist
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> **Note:** The array should be sorted in ascending to descending order
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## Example
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Input: **10,20,30,40,50**
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Element to search: **20**
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Procedure:
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Middle element:**30** and element is less than 30 so search between start to middle -1 index
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Middle element: **20** and yes the middle element is the key to found so return the index=**1**
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Output: **1**
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## Implementation
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- [C](https://github.com/MakeContributions/DSA/blob/main/algorithms/C/searching/Binary-search.c)
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- [C++](https://github.com/MakeContributions/DSA/blob/main/algorithms/CPlusPlus/Searching/binary-search.cpp)
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- [CSharp](https://github.com/MakeContributions/DSA/blob/main/algorithms/CSharp/src/Search/binary-search.cs)
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- [Go](https://github.com/MakeContributions/DSA/blob/main/algorithms/Go/searching/binary-search.go)
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- [Java](https://github.com/MakeContributions/DSA/blob/main/algorithms/Java/searching/binary-search.java)
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- [JavaScript](https://github.com/MakeContributions/DSA/blob/main/algorithms/JavaScript/src/searching/binary-search.js)
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- [JavaScript](https://github.com/MakeContributions/DSA/blob/main/algorithms/JavaScript/src/searching/binary-search-recursive.js)
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- [Python](https://github.com/MakeContributions/DSA/blob/main/algorithms/Python/searching/binary_search.py)
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## Video URL
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[Watch Binary Search Implementation](https://youtu.be/P3YID7liBug)
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## Others
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Solve Problem Related to Binary Search
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[Click Me](https://leetcode.com/tag/binary-search/)
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